The present invention relates generally to ground opener units, such as planting units for forming a furrow in the ground and depositing seeds therein. More particularly, the present invention relates to equipment of the type noted above employing a spring biased scraper devices for cleaning a surface of the disc opener used therein.
Planting assemblies of the type noted above are typically arranged such that the opener disc is held at an angle from the forward direction of travel so that the disc has a leading face and a trailing face. The disc displaces soil laterally as it travels forward and opens a furrow following the trailing face. In wet conditions, soil tends to stick to the trailing face so it is common to provide a scraper to clean the disc. The scraper also acts to prevent loose soil from falling back into the furrow until the seed is properly placed into the furrow. The disc is subject to flexing as lateral forces are applied to the disc when opening the furrow. The scraper must be held close to the disc but not so tightly as to cause a braking action on the disc; therefore it is desirable for the scraper to be allowed to flex and move with the disc's deflection.
The prior art has provided a variety of scraping devices for use in angled disc openers. Reference may be had for example to U.S. Pat. Nos. 4,760,806 and 5,787,994. Another exemplary scraping device employed a bracket which supported the disc scraper and which included a three bolt triangular pattern for adjusting the angle of the bracket. The bracket pivoted on the head of a carriage bolt as the three fasteners were tightened to effect angle adjustment. However, this prior design had a number of disadvantages in that adjustment of one fastener required corresponding readjustment of at least one of the other fasteners; adjustment of the desired angle was complicated and time consuming with the three fastener system and the bracket often became permanently deformed if one fastener was tightened without first loosening the others. Additionally, this rigid adjustment system did not allow the scraper to flex in response to irregularities or flexing of the disc blade.
Another exemplary scraping device is disclosed in U.S. Pat. No. 6,237,696, which describes the use of a resilient pad held against the scraper plate. The resilient pad provides enough force to hold the scraper plate against the disc so as to prevent debris, e.g., soil, from passing between the scraper plate and the surface of the disc, but is made of material that compresses to allow the scraper plate to deflect with deflection of the disc. The resilient pad has a limited range of travel and lacks a well defined point or axis of rotation.